A calculation of the spectroscopic constants for several states of NF
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Abstract:
Spectroscopic constants for NF are determined from a Dunham analysis of potential energy curves computed previously by means of a valence configuration interaction method. Results are presented for several experimentally known and unknown states within the 3 Sigma -, 1 Delta , 1 Sigma +, 1 Sigma -, 3 Delta and 3 Sigma + symmetry species. Where possible, our findings are compared with other calculations and with experiment.Keywords:
Sigma
Force constant
Spectroscopic constants for NF are determined from a Dunham analysis of potential energy curves computed previously by means of a valence configuration interaction method. Results are presented for several experimentally known and unknown states within the 3 Sigma -, 1 Delta , 1 Sigma +, 1 Sigma -, 3 Delta and 3 Sigma + symmetry species. Where possible, our findings are compared with other calculations and with experiment.
Sigma
Force constant
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Abstract Normal vibrations of polyethylene glycol and the perdeuterated species were treated. Intrachain force field was expressed in terms of local-symmetry coordinates. Force constants were adjusted by the method of least squares, with reference to observed infrared and Raman frequencies. A set of force constants was obtained, which reproduces the observed frequencies with an r. m. s. deviation of 0.9%. The values of the force constants thus refined were discussed in comparison with corresponding values of related molecules. Vibrational assignments of the observed infrared absorption bands and Raman lines were revised on the basis of potential-energy distributions refined in the present treatment.
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A search for x rays from the capture of kaons in helium has disclosed neither $K$- nor $L$- series radiation; the upper limit of the x-ray yield is in the range 7-10%. This contradicts results of an earlier measurement, but is in better agreement with related data on kaon-helium scattering. In the same experimental arrangement, the yields of pionic and muonic x rays in helium were also measured. We find anomalously low yields, accompanied by intensity distributions of the $K$-series members in disagreement with the conventional cascade picture of a predominantly circular set of orbits. Monte Carlo cascade calculations could not duplicate the observed results unless weak Stark mixing, in the form of "sliding transitions" ($n,l\ensuremath{\rightarrow}n,l\ifmmode\pm\else\textpm\fi{}1$), was added. Agreement with observation was achieved in muonic, pionic, and kaonic atoms with a single value for the parameter describing the strength of the Stark mixing. Yields and energies of kaonic x rays in other light elements, Li, Be, and C, were also measured. Yields of x rays from muonic and pionic capture in these elements were remeasured also, and cascade calculations like those for helium repeated. In these elements the addition of Stark mixing is not needed to achieve agreement with experiment. In the pionic atoms $2p$-state absorption rates, and in kaonic atoms $3d$-state absorption rates for He, Li, Be, and C can be derived from the experimental data and compared with theoretical values, with good agreement. In addition to the identifiable kaonic transition lines also observed by Wiegand and Mack, additional lines not ascribable to kaonic atoms were found in all three elements. After careful consideration of possible origins of these lines, we ascribe the two lithium lines to $M\ensuremath{\alpha}$ and $M\ensuremath{\beta}$, and the Be line to $M\ensuremath{\alpha}$ transitions in $\ensuremath{\Sigma}$-hyperonic atoms. Such atoms are formed if ${\ensuremath{\Sigma}}^{\ensuremath{-}}$ hyperons from kaon capture (whose abundance is about 15%) are slowed down and stopped in the target. The observed yields and energies are consistent with this interpretation, and with no other we have been able to invent. A line in C, however, cannot be ascribed either to kaonic or $\ensuremath{\Sigma}$ atoms, and appears to be a pionic $L\ensuremath{\alpha}$. Why such a line appears only in C is not understood.
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The synthesis and structural characterization of three mixed-valence π-cation radical derivatives of (octaethylporphinato)metal(II) species, [M(OEP•/2)]2+, (M = Ni, Cu, and (Zn,H2)), are reported. The species thus have the same formal ring oxidation level as the photooxidized special pair of photosynthetic reaction centers. The complexes display unique binuclear structures with cofacial porphyrin rings with mean plane separations of 3.20−3.32 Å, ring center to ring center distances of 3.50−3.55 Å, and lateral shifts between the two rings of 1.16−1.53 Å. These inter-ring geometries are distinctly different from either those of "classical" π-cation radical derivatives or those of dimers formed by neutral species. The different inter-ring geometries suggests that there are inherent inter-ring geometries that depend principally on the oxidation level of the porphyrin rings.
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The energies for the electronic states X1Σ+ and C′1Δ of BH molecular are scanned using SAC/SAC-CI(Symmetry Adapted Cluster/Symmetry Adapted Cluster-Configuration Interaction) with the basis sets 6-311G**.Then the scanned results are fitted to MurrellSorbie function.In the last,the spectroscopy constants and force constants are also calculated.These results are better than other theoretical results compared with the experimental ones.
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Experimental data on the positions and widths of the vibrational energy levels of the C 3Πg Rydberg state of molecular oxygen are interpreted. The energy levels are described as resonances in the elastic scattering of oxygen atoms in the open 1 3Πg valence state caused by a coupling to the closed C 3Πg Rydberg state. The coupled scattering equations are set up with an empirical valence potential energy curve and Rydberg-valence interaction potential and it is shown that the energy level positions and widths can be reproduced by an interaction of 63 meV and a potential energy curve that crosses the Rydberg curve on the attractive part of its outer limb.
Rydberg constant
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